Activation Of Î±7 Nicotinic Receptor Affects App Processing By Regulating Secretase Activity In Sh-Ep1-Î±7 Nachr-Happ695 Cells
Multiple lines of evidence have implicated that nicotinic acetylcholine receptor (nAChR) may be an important therapeutic target for the treatment of Alzheimer's disease (AD). Although there are reports suggesting a link between alpha7 nAChR subtype and AD, there has been little report on the mechanism. The present study investigates whether and how Î±7 nAChR activation affects APP695 processing in SH-EP1 cell model. Cell line co-expressing Î±7 nAChR gene and human amyloid precursor protein 695 (hAPP695) gene were constructed by stable transfection. Expression of Î²-amyloid, Î±-form of secreted APP (Î±APPs) and APP1695 was measured by ELISA, western blotting and real-time PCR respectively. Additionally, Î±, Î², and Î³-secretase activities were also analyzed in constructed SH-EP1-Î±7 nAChR-hAPP695 cell line. The results showed that SH-EP1-Î±7 nAChR-hAPP695 cell line, expressing both hAPP695 gene and Î±7 nAChR subtype gene, was constructed successfully. The secreted AÎ² was decreased and Î±APPs was significantly increased by non-selective nAChR agonist nicotine (10 Î¼M) and specific Î±7 nAChR agonist GTS-21 (1 Î¼M), and APP expression was not affected. Furthermore, specific Î±7 nAChR antagonist methyllycaconitine (MLA) reversed the alterations induced by activation of Î±7 nAChR. CTF-Î± was increased and CTF-Î³ was decreased when treated with nicotine (10 Î¼M). In addition, the results of enymatic activity analysis showed that nicotine (1 Î¼M) and GTS-21 (0.1, 1 Î¼M) decreased Î³-secretase activity, but has no effects on Î±-secretase activity and Î²-secretase activity. Our findings demonstrate that, through regulating Î³-secretase activity, Î±7 nAChR activation reduces APP processing in amyloidogenic pathway, and at the same time enhances APP processing in non-amyloidogenic pathway. The constructed SH-EP1-Î±7 nAChR-hAPP695 cell line might be useful for screening specific nAChR agonists against AD. Â© 2010 Elsevier B.V.
Digital Object Identifier (DOI)
Nie, Hui Zhen; Shi, Sha; Lukas, Ronald J.; Zhao, Wen Juan; Sun, Yong Ning; and Yin, Ming, "Activation Of Î±7 Nicotinic Receptor Affects App Processing By Regulating Secretase Activity In Sh-Ep1-Î±7 Nachr-Happ695 Cells" (2010). Neurobiology. 183.